Two-Dimensional Antiferroelectricity in Nanostripe-Ordered In_{2}Se_{3}

Area of Science:

• Condensed Matter Physics
• Materials Science

Background:

• Two-dimensional (2D) layered materials offer a unique platform for exploring physics at reduced dimensions.
• Previous research has demonstrated various exotic properties in 2D materials at their fundamental limit.

Purpose of the Study:

• To report the first experimental discovery of in-plane antiferroelectricity in a 2D material.
• To elucidate the nanostructure and underlying physics of β^{'}-In_{2}Se_{3}.

Main Methods:

• Experimental investigation using optical and electron microscopy.
• Theoretical validation through first-principles calculations.

Main Results:

• Experimental confirmation of in-plane antiferroelectricity in β^{'}-In_{2}Se_{3}.
• Observation of unusual nanostripe ordering with local ferroelectric polarization and antipolar neighboring nanostripes.
• Demonstration that this phenomenon is confined within the 2D layer and persists down to single-layer thickness.

Conclusions:

• The study establishes β^{'}-In_{2}Se_{3} as a novel 2D material exhibiting in-plane antiferroelectricity.
• The findings resolve a long-standing debate regarding the superstructure of β^{'}-In_{2}Se_{3}.
• This discovery opens new avenues for exploring 2D ferroelectric and antiferroelectric phenomena.